Machine for grinding points.



J. OHANIAN. MACHINE FOR GRINDING POINTS. APPLICATION FILED oo'r.1a. 1907.

902,598. A Patented Nov.8, 1908.

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JOHN OHANIAN, OF BOSTON, MASSACHUSETTS.

MACHINE FOR GRINDING POINTS.

T0 all whom it may concern:

Be it known that I, JOHN OHANIAN, a subjct of the Sultan of Turkey, residing at 7 *ricson avenue, Allston, Boston, Massachusetts, have invented a certain new and useful Improvement in Machines for Grinding Points, of which the following is a specification, reference being had therein to the accompanying drawings.

In the manufacture of certain articles, it is necessary to grind them so that a point of a peculiar character is obtained. This is especially true in the manufacture of points for talking machines, when the points are tipped with a diamond, sapphire or other hard stone. I-Ieretofore, so far as is known to me, it has been impossible to give these points the perfectness of form which is desirable.

My invention provides a simple machine, by means of which points may be ground very rapidly and with the desired accuracy.

The machine embodying my invention is exceedingly simple and is adapted to be used by jewelers, diamond cutters and the like. It may also be used for grinding a variety of other articles.

The invention will be fully understood from the following description taken in connection with the accompanying drawings, and the novel features will be pointed out and clearly defined in the claims at the close of the specification.

In the drawings,-Figure 1 is an elevation of a machine embodying my invention. Eig. 2 is a side elevation thereof. Fig. 3 is a top plan view of a portion of the machine.

Referring to the drawings,-at 11 is indicated a table or other suitable support for the machine.

At 12 is shown a stand ard which is secured to the table 11 by means of the thumb screw 13. The standard 12 may be turned into any of various positions by means of the slots 14, 15, in the table 11, and after being moved from one osition to another, may be again fixed in p ace by means lof the thumb screw 13. The standard supports an upright 16 of cylindrical form mounted in a corresponding bearing in the standard 12 to ermit the parts to swing about a vertica axis. A thumb screw 17 is provided to fix the said upright 16 in place when desired.

To the upper end of the upright 16 is pivoted at 161 a curved frame 18 which is provided with a slideway 19 in the form of the arc of a circle and supports by means of an Specification of Letters Patent.

Application filed October 18, 1907.

Patented Nov. 3, 1908.

Serial No. 397,968.

intermediate or swinging frame 20 a grinding spindle 21. The article to be ground is placed in a chuck 22 at the lower end of the said grinding spindle 21 and is held against the surface of a grinding wheel 23 which is rapidly rotated by means of the belt 24 and a pulley 25. Suitable abrasive material selected according to the character of the material of which the point to be ground is made is applied to the upper surface of the said grinding wheel 23. It will be understood that the said grinding wheel may be raised or lowered as desired, thereby swinging the frame about the pivot 161 and presenting the point to the grinding wheel at a different angle, or the said grinding wheel may be somewhat inclined.

The swinging frame 20 is formed of two radial pieces 35 and 36 and a curved slide 27 of a shape corresponding to the shape of the slideway 19. The rotating grinding spindle 21 is supported in two bearings, one, 28, at the junction of the radial arms 35 and 36 and the other, 281, on the curved slide 27 with the capacity of rotation. The said spindle 2l is caused to rotate by means of a small grooved wheel 29 driven by the belt 30 from another grooved wheel 31 supported on the shaft 32 on a fixed arm 33 at the back part of the machine. A crank 34 is fixed to the up per end of the said spindle 21 and is connected by means of a universal joint 35 and pitman 36 with a fixed portion 37 of the frame of the machine. See Fig. 3. It will be seen that by the rotation of the spindle 21 the attached crank 34 will cause the swinging frame 20 to oscillate back and forth in the slide way 19, thus giving to the point 38 a swinging motion at the same time that it rotates about its vertical axis. The point is also at that time being acted upon by the abrading surface of the grinding wheel 23.

As previously stated, the slide way 19 and the slide 27 of the swinging frame 20 are each in the form of arcs of a circle. The center of this circle is the lowermost extremity of the finished point so that the oscillation of the spindle and frame is about this point as a center. During the operation of the machine, the point is rocked as described at the same time that it is being rotated.

By pivoting the frame 18 to the upright 16, the operator is enabled to lift up the point from the grinding wheel when it is desired to examine the point or to change the abrasive material on the grinding wheel and the point during the grinding operation is held in contact with the upper surface of the grinding wheel with a force supplied by the weight of the frame and attached parts. Additional weight may also be applied to the frame when desired.

I claim as my invention:

l. In a machine for grinding points, the combination of a spindle rotatable about its Vertical axis, a frame for the said spindle, one portion of which is an arc of a circle whose center is the point to be ground, a slideway for the said curved portion of the frame, and means for causing the said frame to oscillate in the said slideway.

2. The improved machine for grinding points comprising a spindle rotatable about its axis, a frame, the upper portion of which is curved in the li'orm of' an arc of a circle, a second frame in which the 'first mentioned frame is slidably mounted, a crank on the said spindle, and a connection between the said crank and a iiXed part of the machine whereby the rotation of the said spindle causes the said frame to oscillate in the slideway and to rock on the said point during grinding.

In testimony whereof I aHiX my signature,`

in presence of two witnesses.

JOHN OHANIAN.

Witnesses:

GEORGE P. DIKE, ALICE H. MORRISON. 

